/Engine/Source/Runtime/MeshConversion/Public/DynamicMeshToMeshDescription.h
Transfer PolygroupLayers from DynamicMesh AttributeSet to MeshDescription. Will copy to existing MeshDescription TriangleAttributeif one with the same name exists. Otherwise will register a new one.
void ConvertPolygroupLayers ( const [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) * MeshIn, [FMeshDescription](API\Runtime\MeshDescription\FMeshDescription) & MeshOut, const [TArray](API\Runtime\Core\Containers\TArray)< [FTriangleID](API\Runtime\MeshDescription\FTriangleID) > & IndexToTriangleIDMap )